As one type of image processing apparatuses as electronic equipment, an image forming apparatus (typically a copy machine) for forming an image on a sheet of recording paper has been introduced to many places of business (companies and offices). In such a place of business, it is a common practice to have an image forming apparatus having a printer function or a copy function connected to a network and to share the apparatus by a plurality of users. An MFP (MultiFunction Peripheral) as one type of such image forming apparatuses has a plurality of basic operational modes including a copy mode, a facsimile mode (hereinafter facsimile will be also denoted as FAX), a network compatible printer mode and a scanner mode.
The image forming apparatus has, for example, a NIC (Network Interface Card) as an interface for connection to the network. The NIC has a terminal, to which a communication cable such as a UTP (Unshielded Twisted Pair) cable is connected, so that the image forming apparatus is connected to the network. When connected to the network, the image forming apparatus can realize the functions of receiving and printing image data from a terminal such as a PC connected to the network, transmitting an image data obtained by scanning a document by attaching it to an electronic mail, or transferring the image data to a computer server using FTP.
Recently, wireless network environment has come to be advanced, since it eliminates the necessity of hard-wiring and facilitates installment of equipment. As a device for wireless connection, a compact USB adapter for wireless LAN (hereinafter referred to as a USB wireless LAN adapter) in compliance with international standard such as IEEE802.11 series has been widely used. When a USB wireless LAN adapter is mounted on an apparatus such as a PC, the PC becomes connectable to a router, an access point or the like by radio wave in the frequency band of, for example, 2.4 GHz. Further, since Wi-Fi has made it possible to verify inter-connectability among manufacturers of wireless LAN devices, wireless network connections are growing more popular.
By way of example, Japanese Patent Laying-Open No. 2011-82677 (hereinafter referred to as '677 Reference) discloses a USB wireless LAN adapter that changes the methods of communication (isochronous transfer or bulk transfer) depending on the type of communication data (streaming data or not) and on the situation of communication (isochronous transfer is in progress or not).
A USB port of a PC or the like is used for connecting various peripheral devices, in addition to the wireless LAN adapter. As a USB-connectable peripheral device, a USB memory is widely used. A USB memory is of large capacity, small, light-weight, portable and easy-to-handle and, therefore, it is used for moving data of a large data size, such as image data, to another device.
Image forming apparatuses having a number of USB ports have been known. In such an image forming apparatus, a USB wireless LAN adapter is used in a constantly connected state, always connected to one USB port (always kept connected while the power of image forming apparatus is ON), to enable wireless connection to the network. It is possible for a user to insert USB memory to another USB port of the image forming apparatus to input image data to be printed stored in the USB memory to the image forming apparatus, or to store image data of a scanned document or the like in the USB memory to move to another device such as a PC.